June 8, 212 Have agricultural management practices (AMPs) improved water quality?: A case study in Sugar Creek Jeff Frey U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey National Water-Quality Assessment Program (NAWQA)
Understanding trends Hydrology How does the water (and chemicals) move to streams and groundwater Chemical properties Does the chemical dissolve in water or attach to sediment Wet vs Dry years Do changes in water quality reflect changing streamflow instead of changing management practices?
Sugar Creek: Extensively Studied Since 1992 (17 years) Streamflow monitored since 1967 Nutrients (1992-21) 354 samples Sediment (1992-21) 325 samples Pesticides (1992-21) 325 samples Ecological community sampling 12 years Algae, fish, invertebrates Habitat
Sugar Creek is a Heavily Agricultural Basin 95 mi 2 basin Corn/ Soybeans Till plain Heavily tiled
Ground Water and Precipitation
Overland Flow
Tile Drain
How Do Nutrients Get Into Streams?
Has Water Quality Improved with the Implementation of Agricultural Management Practices?
What are agricultural management practices? Conventional tillage Conservation tillage
No Till Conservation Tillage Increased Through the 199 s From Evans and others, 2 Soybeans 199 2% 1998 72% 2 74% Corn 199 2% 1998 5% 2 8% Hancock County
Sediment Concentrations over Time 3, 2,5 Discharge (ft3/sec) Suspended Sediment (mg/l) 5 45 4 2, 35 3 1,5 25 1, 2 15 5 1 5 May-92 May-93 May-94 May-95 May-96 May-97 May-98 May-99 May- May-1 May-2 May-3 May-4 May-5 May-6 Sugar Creek
Sediment Concentrations over Time 2. Log Median Suspended sediment concentrations 1.8 1.6 1.4 1.2 1..8 1992 1994 1996 1998 2 22 24 26 Year Sugar Creek
Sediment Concentrations over Time 3, 2,5 2, 1,5 1, Discharge (ft3/sec) Suspended Sediment (mg/l) 1992-26: No significant change 1992-1999: 3.6% decrease p-value =.36 5 45 4 35 3 25 2 15 5 1 5 May-92 May-93 May-94 May-95 May-96 May-97 May-98 May-99 May- May-1 May-2 May-3 May-4 May-5 May-6 Sugar Creek
What are agricultural management practices? Riparian buffers Tile drains
Nitrate Concentrations over Time Discharge Nitrate 3, 14 2,5 12 2, 1 8 1,5 6 1, 4 5 2 Sugar Creek
Tile Drain Variability The type of tile drain system within the watershed greatly affects the transport and type of nutrient and sediment in the stream, specifically: Surface connected Cloudy Contains sediment, total forms sub-surface inlets Usually clear Contains mostly dissolved forms Surface Subsurface
Nitrate Concentrations over Time Discharge Nitrate 3, 14 2,5 1992-26: No significant change 2, 12 1 1992-1999: 14.3% decrease 1,5 p-value =.363 1, 8 6 4 5 2 Sugar Creek
Population in Hancock County Has Increased Hancock County, Indiana 4 Annual change in population (%) 3.5 3 2.5 2 1.5 1 1992 1994 1996 1998 2 22 24 26 28 Year Sugar Creek
Sensitive fish species have increased in Sugar Creek Percent Relative Abundance of Bigeye chub and shiners 12 1 8 6 4 2 Percent relative abundance of Bigeye Chub and Bigeye Shiner at Sugar Creek, Indiana, 1993-28 Relative abundance No-till 1985 199 1995 2 25 21 1 9 8 7 6 5 4 3 2 1 Percent No-till Sugar Creek 1993-28
Sensitive fish species have increased in Sugar Creek Percent Relative Abundance of Bigeye chub and shiners 12 1 8 6 4 2 Percent relative abundance of Bigeye Chub and Bigeye Shiner at Sugar Creek, Indiana, 1993-28 Relative abundance No-till 1985 199 1995 2 25 21 1 9 8 7 6 5 4 3 2 1 Percent No-till Sugar Creek 1993-28
Sensitive fish species have increased in Sugar Creek 6 Abundance of the Northern Studfish at Sugar Creek, Indiana, 1993-28 1 Number of Northern Studfish 5 4 3 2 1 9 8 7 6 5 4 3 2 1 Percent of No-till 1985 199 1995 2 25 21 Sugar Creek 1993-28
Sensitive fish species have increased in Sugar Creek 6 Abundance of the Northern Studfish at Sugar Creek, Indiana, 1993-28 1 Number of Northern Studfish 5 4 3 2 1 9 8 7 6 5 4 3 2 1 Percent of No-till 1985 199 1995 2 25 21 Sugar Creek 1993-28
Summary Long term water quality and biological monitoring can help show improvements in water quality Implementation of Best Management Practices has improved water quality depending upon the BMP and the compound Multiple stressors (ag and urban) can influence trends Sugar Creek, Indiana
Indiana Water Science Center Web Page: http://in.water.usgs.gov/ Jeff Frey 317-6-2751 jwfrey@usgs.gov